agrégation

Traductions

• anglais

  Date : 1990

  Définition

  A group of two or more particles.
  
  A general term describing the combination or coalescence of particles dispersed in a suspension into clusters or clots, which either precipitate or are removed by filtration.

  Notes :

  Such particles may be macromolecules of proteins, soaps, or other colloids (aggregates of which are called micelles), or larger particles, such as red cells in blood, rubber hydrocarbon in latex, and fat particles in milk.
  
  If the particles are "cemented" together a hard aggregate is formed. Soft flocculates are also classified as aggregates, but such aggregates do not function rheologically as single particles (as do hard aggregates).
  
  There are three major types of aggregation: (1) agglutination, which is chiefly the cohesion of bacterial cells, as in antigen-antibody reactions; (2) coagulation, the irreversible clotting of proteins, etc., brought about by electrolytes, enzymes, or heat; and (3) flocculation, the formation of clumps of dispersed colloidal solids such as carbon black in rubber mixes.

  Terme :

  1. aggregation